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Danfoss AFP 2/VFG 2 Operating Manual page 7

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AFP 2 / VFG 2 (21) DN 15-250, VFG 22 (221) DN 65-250
ENGLISH
Safety Notes
Prior to assembly and commissioning to
avoid injury of persons and damages of the
devices, it is absolutely necessary to carefully
read and observe these instructions.
Necessary assembly, start-up, and maintenance work
must be performed only by qualified, trained and
authorized personnel.
Prior to assembly and maintenance work on
the controller, the system must be:
- depressurized,
- cooled down,
- emptied and
- cleaned.
Please comply with the instructions of the system
manufacturer or system operator.
Definition of Application
The controller is used for diffe rential pressure control
of water and water glycol mixtures for heating, district
heating and cooling systems.
The technical data on the label plates determine
the use.
Scope of Delivery ❶
*) Impulse tube AF, accessory
Assembly
Admissible Installation Positions ❷
media temperatures up to 150 °C:
Can be installed in any positi on.
media temperatures > 150 °C.
Installation permitted only in horizontal pipelines
with the actuator oriented downwards.
Installation Location and Installation
Scheme ❸
Return mounting
Flow mounting
Valve Installation ❹
1. Install strainer
before the controller.
2. Rinse system prior to installing the valve.
3. Observe flow direction
on valve body.
Flanges
in the pipeline must be in
parallel position and sealing surfaces
must be clean and without any damage.
4. Install valve.
5. Tighten screws crosswise in 3 steps up
to the max. torque.
Actuator Installation ❺
The actuator stem must be screwed into
the valve stem. Spring on the pressure
actuator is factory adjusted (released)
for proper installation.
1. Remove the spindle protection cup and release
the valve spindle by removing the nut, washer
and cardboard tube.
2. Align the actuator stem with the valve stem,
connect both stems and turn gently the whole
pressure actuator clockwise with both hands,
until the stems are fully connected (valve
stem fully screwed into the actuator stem).
3. Release the uninon nut by pulling out
the blocking spring.
4. Tight the union nut
5. Release the pressure actuator by turning it counter
clockwise for approximately half a turn.
6. Observe the position of impulse tubes connection
to the valve and align the actuator accordingly.
7. Hold the actuator in the position and tight the
union nut to the valve with 100- 120 Nm torque.
Impulse Tube mounting ❻
Which impulse tubes to use?
The impulse tube set AF (2×)
❻①
Order No.: 003G1391
AQ26905314366601-010203
or use the following pipes:
Stainless steel
Steel
Copper
Connection of impulse tubes
Installation in return flow
Installation in supply flow
Connection to the valve ❼
1. Remove plug
2. Screw in threaded joint G 1/4
Torque 40 Nm.
- or -
Connection to the Pipeline ❽①
No connection downwards/upwards
bring dirt/air into an impulse tube.
1. Cut pipe in rectangular sections
2. For copper pipe:
insert sockets
3. Verify the correct position of the cutting ring 
4. Press impulse tube
up to its stop.
5. Tighten union nut
When installing seal pots
observe the Installati on Instructions
for the seal pots.
Insulation ❾
For media temperatures up to 120 °C the pressure
actua tor may be insulated
Dismounting ❿
Danger
Danger of injury by hot water
Prior to dismounting depres surize system
or use shut off valves on the impulse tubes!
Carry out dismounting in following steps:
1. Fasten pressure actuator with the safety bands
to the fixed points in surroundings
2. Before releasing the actuator, fully release
the union nut
3. Hold the pressure actuator with both hands,
and release it by turning it counter clockwise
~30 turns. During turning, control the actuator
weight all the time to prevent unexpected fall
of detached actuator.
4. Carefully remove the actuator from the valve.
Before installing actuator back to the valve, setting
spring must be fully released again.
Leak and Pressure Test ⓫
"Danger of injury by heavy weight of
pressure actuator. When dismounting
the pressure actuator from the valve,
control the actuator weight all the time
to prevent unexpected fall of detached actuator
and potential injuries due to the heavy weight!"
To prevent damages on the diaphragm pressure
must be constantly and simultaneously increased
at the + and − connection 
pressure is reached.
In case of higher test pressu res, remove impulse tubes
at the pipelines
Observe nominal pressure
Max. test pres sure must not exceed the plant testing
pressure and must always be lower than 1.5 × PN
Non-compliance may cause damages at the actuator
or valve.
can be used:
DIN 17458,
Ø 10×0.8
DIN 2391
Ø 10×1
DIN 2391
Ø 10×1
DIN 1754
in the system
❻②
at the valve.
with copper seal,
, could
and deburr.
on both sides.
into the threaded joint
Torque 40 Nm.
❽⑧
, please
.
until the max testing
.
of the valve.
Filling the System, Start-up ⓬
The return flow pressure
exceed the supply flow pressure
Non-compliance may cause damages at
the controller
.
1. Open shut-off devices
available at the impulse tubes.
2. Slowly open valves in the system.
3. Slowly open shut-off devices
4. Slowly open shut-off devices
Putting out of Operation
1. Slowly close shut-off devices
2. Slowly close shut-off devices
Differential Pressure Setting ⓭
Set-point range see rating plate
1. Start-up of system, see section
2. Set flow rate on a motorized valve
which the differential pressure is controlled,
.
to about 50 %
3. Adjustment
• Observe pressure indica tors
• Turning to the right
(stressing the spring)
• Turning to the left
redu ces the
set-point (un-stressing the spring)
4. The set-point adjuster
5. Release the not yet used pointer
set position and fix it with the screw
Dimensions ⓮
Flanges: connection dimensi ons acc. to DIN 2501, seal form C
© Danfoss | 2021.08 | 7
must not
.
that are possibly
in the supply flow.
in the return flow.
in the supply flow.
in the return flow.
.
over
.
increases the set-point
may be sealed.
, move it to the

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